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Continuing Studies > Winemaking > Flashcards

Winemaking Flashcards

1
Q

Why do late harvest/botrytised grapes get “stuck” fermentation

A

Typically contain more fructose than glucose. Yeasts quickly consume glucose but struggle to metabolize fructose
*both are the main fermentable sugars

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2
Q

Device to measure sugar content in the field? In the winery?

A

Refractometer
Hydrometer

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3
Q

Brix

A

a measure of the amount of dissolved solids in a liquid via its specific gravity
*used to measure sugar dissolved in liquid

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4
Q

TA

A

Tirtratable acidity: the perception of sour
*higher = more sour

typically in the range of 4 to 9 grams per liter tartaric acid equivalents

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5
Q

pH in wine

A

Wine is usually around pH 3 or 4 (logarithmic - so 3 has 10x more acidity than 4)

A measure of the concentration of hydrogen ions (or protons) in a solution

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6
Q

Total Acidity

A

A measure of organic acids

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7
Q

Catechins

A

small polyphenols extracted from skins and seeds; responsible for bitterness in wine

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8
Q

Reductive approach to fruit processing/handling

A

Goal: preserve aromatics / freshness, fruit, floral flavors, prevent browning

Method: dry ice (carbon dioxide), inert gas, sulfur dioxide to protect must during processing

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9
Q

Purpose of intentionally oxidizing white wine must?

A
  • juice turns brown initially but clarifies throughout fermentation.
    *Susceptible compounds oxidize and are discarded as lees
  • finished wine is potentially less fruity but more resilient against post-fermentation oxidation
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10
Q

Sorting

A

*method: hand, shaker tables, optical sorters
*cluster sorting removes compromised bunches and MOG
*Berry sorting for de-stemmed fruit removes shot berries, stem, insects

Sorting for skin contact wines is more critical since they have more time to extract the bad stuff. Light/quick presses aren’t as critical.

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11
Q

Laccase

A

A particularly virulent oxidation enzyme produced by botrytis
* not deterred by sulfur dioxide or alcohol

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12
Q

Cluster vs. De-stemming in white winemaking

A

*de-stemmed and/or crushed fruit imparts more texture/skin influence

  • whole cluster press = clear juice, few skin-derived compounds including phenolics that cause bitterness
    ** whole cluster is required for many sparkling wines since skin contact is undesirable
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13
Q

ABV inside carbonic maceration berries?

A

2% - then enzymes are denatured and fermentation stops

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14
Q

Stems in fermentation

A

Increase amounts of phenolic compounds, potassium

  • often results in lighter colored, more tannic wines with higher pH and lower alcohol
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15
Q

Rosé methods

A
  1. Direct press: whole cluster, treated like white wine. Essentially a red wine made with no skin contact.
  2. Maceration/Saignée: quick maceration then juice is bled off. Red wine with very short skin contact.
  3. Blending: Rosé Champagne and few other styles
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16
Q

Saignée

A

Red wine technique - concentrates must
* juice is removed from red wine tank to increase proportion of skins to concentrate that wine
* this juice can become rosé - but since original purpose was red wine, it has a higher pH and more sugar so may require adjustment for balance

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17
Q

Cold Soak

A

Red wines held inoculated for days to weeks at cold temps
* fruit enzymes break down skins, starting extraction process
* populations of wild yeasts build (favored over Saccharomyces at cooler temps)
* some believe increases color extraction

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18
Q

Thermovinifcation

A

GOAL: accelerate extraction

WHY: saves tank space, fixes low quality fruit, denatures laccase in botrytised wine which prevents excessive oxidation

METHOD: 140 - 180º for 30min to 24hrs. Press directly after heating then fermentation commences
Little tannin extraction.

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19
Q

Flash Detente

A

GOAL: accelerate extraction

WHY: saves tank space, fixes low quality fruit, denatures laccase in botrytised wine which prevents excessive oxidation

METHOD: grapes rapidly brought to 185º then immediately cooled. Complete destruction on cellular level - looks like jam. Settled, drained, pressed, then fermented.
Little tannin extraction.

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20
Q

Press Cut

A

The separation of juice during the pressing process.

Free run, the press cut, and the hard press - as the press applies increasing pressure, the decision of when to separate the free run/mid from the heaviest press

  • typically based on taste, looking for changes in aromatics, acidity, the level of oxidation, and tannnin extraction
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21
Q

Free run

A

juice liberated without application of pressure
* free run and light press are used interchangeably with white wine often
* for reds, this is everything that comes out when you open the valve - prior to pressing the rest to end extraction

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22
Q

Press Wine

A

~20% of total press for red wine
Once the free run drains off (which is most off it) - the portion that you need to press out of the skins
* red press wine is more tannic

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23
Q

3 press cuts for white wine?

A

Free Run, Light Press, Heavy Press

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24
Q

2 basic types of presses and which is better for quality?

A

Batch press (the quality option)
Continuous Press

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25
Q

Basket Press

A

Style of vertical batch press used since the Middle Ages

  • grapes are loaded into basket. Pressure is applied to lid, presses down on grapes releasing juice

**pressure applied is uneven and results in low yields on unfermented berries - thus preferred for reds, not whites

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26
Q

Preventing oxidation during the press?

A

Dry ice
Sulfur dioxide

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27
Q

Post-Press Clarification/Solids Removal

A
  • débourbage followed by racking/decanting the juice off
  • filtration/centrifugation
  • flotation - gas floats solids to top to be skimmed off
  • bentonite to bind with solids

Solids inclusion increases volatile thiols and viscosity - contributes to flinty character that many call reduction. Solids contain yeast nutrients so may be included to help with fermentation and increase esters.

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28
Q

Methods to increase potential alcohol

A
  • Reverse Osmosis: extracts water
  • Chaptalization
    *addition of grape concentrate: sugar, acid, color compounds
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29
Q

Methods for potential alcohol reduction

A
  • adding water to must
  • irrigating vines just before harvest
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30
Q

Methods to de-acidify a wine

A
  • Malolactic conversion
  • adding salts that react with tartaric salts that settle out of wine
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31
Q

Oenococcus oeni

A

Lactic acid bacteria frequently responsible for malolactic conversion

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32
Q

Acetic acid bacteria

A

Convert alcohol to vinegar. Spoilage organism.
* requires oxygen for growth/activity -thus, in damaged and botrytised fruit
*protecting the wine from oxygen by topping up and by maintaining reasonable levels of SO2 keeps the population in check

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33
Q

Saccharomyces

A

alcohol tolerant and SO2 tolerant - can finish a fermentation. Most yeasts cannot.
* low nutrient levels cause yeasts to stress and create highly reductive aromas and stuck ferments

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34
Q

Pied de Cuve

A

A portion of yeast-rich, already fermenting grape must used to inoculate - basically a sourdough starter, but for wine

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35
Q

Glycolysis

A

The 1st 10 steps of fermentation of yeasts converting sugar into energy

  1. evaluation of carbon
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36
Q

3 stages of yeast fermenation

A
  1. lag phase: yeast adapts to the high-sugar environment, little population growth
  2. exponential phase: building up a critical population
  3. stationary phase: fermentation - population is maintained until fermentation finishes and cell counts decrease
37
Q

Oxygen during fermentation

A

Yeasts need oxygen for healthy cell walls to survive the high alc environment
* splashing, open pumpover, direct injection of air or oxygen
**no need to worry about negatives of oxidation here - yeasts ingest the oxygen immediately before it can react with wine

38
Q

Low nitrogen in fermentation

A

Nitrogen-deficient yeasts produce hydrogen sulfide (rotten egg smell) and stuck fermentations
*YAN: Yeast assimable nitrogen
*can augment that with diammonium phosphate (DAP)

39
Q

Mercaptans

A

bad thiols
*if not managed right, hydrogen sulfide will react to create other sulfides - methane and ethane thiols, responsible for rubber, skunk, onion smells
**aerative cap management, additional nutrients or oxygen to bolster fermentation, or copper fining can fix these

40
Q

3-mercaptohexanol

A

passionfruit, grapefruit smells in Sauv Blanc

41
Q

Yeasts’ temp range for fermentation? Most active range?

A

45 - 95º
mid-70’s to mid-80’s = most active

42
Q

White wine fermentation temperature

A

Generally mid 40s to mid-60sºF
*cooler preserves more delicate aromas and crisp style. Warmer brings out more floral character + riper richer fruit

43
Q

Red wine fermentation temperatures

A

Mid-70’s to low 90’s
*facilitates extraction from skins
*higher end of the range extracts more tannin and phenolic compounds.. darker, fuller bodied reds

44
Q

Cap management

A

Remontage / Pumpovers
Pigéage / Punchdowns
Délestage / Rack and Return
or… submerged cap (Piedmont)

CO2 pushes grape skins up - forming the cap and separating it from the juice
*homogenizes contents of tank - essential skin to juice contact
* regulates fermentation temps by breaking up hot/cold pockets
* discourages growth of acetic bacteria
*introduces oxygen for yeast health

45
Q

3 cap management techniques and their French names

A
  1. Remontage / Pumpovers: juice is pumped from bottom of tank and redistributed over top - might use sprinkler for even wetting of cap
  2. Pigéage / Punchdowns: mixes the tank by pushing the cap down into the liquid portion
  3. Délestage / Rack and Return: liquid is drawn off and put in another container, leaving the skins in the original spot. Liquid is then pumped over top of original tank.
    ** most efficient, most complete mixing, and lowers fermentation temp

**or cap may stay submerged (ex: piedmont)

46
Q

Cap management relationship with extraction?

A

More cap management = more extraction
1 -2x a day during fermentation - or 3 - 6x for bigger extracted styles

47
Q

Methods to stop fermentation

A
  • temperature
  • SO2
  • filtration or centrifugation which remove the yeast
  • fortification with a high proof spirit
48
Q

Bâtonnage

A

“lees stirring”
Introduces oxygen that is consumed by yeast
* re-suspends lees that fell to bottom of barrel
* during fermentation, this encourages ferment to finish
* during aging, improves mouthfeel by incorporating mannoproteins and other products of autolysis
** in general, keeps lees fresh and reduces reductive aromas

49
Q

Stuck Fermentation

A

Stressed yeast - due to ferment temps, sudden temp change, or competition
* warming and frequent mixing keep yeasts suspended and give more access to sugar

50
Q

Malolactic Conversion

A
  • inhibitors: pH below 3.2, alc above 14.5%, low temps, sulfites
  • 60 - 85º is good, 70º is ideal
  • starts slow - oft lasts weeks to months
    *preferable to start after primary: reduces yeast/bacteria competition, prevents stuck ferments, and malo bacteria convert sugar to VA
51
Q

Buttery flavor

A

Diacetyl: side product of malo conversion - malolactic bacteria will continue to break it down even after conversion completes
* sulfur immediately after malo conversion preserves it - waiting til it dissipates eliminates impact
*citric acid additions: lactic acid bacteria converts citric to diacytel

52
Q

Methods to stop malolactic conversion

A
  1. sulfur dioxide
  2. lysozyme (an enzyme that destroys LAB)
  3. filtration

When not intended, wine is sulfured asap following primary fermentation and is almost always sterile-filtered prior to bottling to prevent refermentation in bottle.

53
Q

Timing of malolactic conversion

A
  • after primary, unsulfered wine is at spoilage risk - some prefer to start and finish asap
  • waiting allows wine to be stored unsulfed longer, aka less sulfur use overall
  • for color: right after primary, anthocyanins are reacting with other compounds to create stable pigments. Malo eats those compounds - so if conversion started before color stabilized, it won’t stabilize
54
Q

Micro-oxygenation

A

Controlled introduction of oxygen over time - can be an economical way to mimic barrel aging for tank wine

Benefits: soften tannin, stabilize color, and reduce herbaceous, vegetal, or reductive aromas

Cliquage is similar but different - larger dose of oxygen that mimics the amount you’d see with racking

55
Q

Cliquage

A

Oxygenation technique that introduces a larger dose of oxygen that mimics the oxygen exposure you’d experience with racking

56
Q

2 French oak species

A

Quercus robur
* coarser grain, more tannic

Quercus petraea (Quercus sessilis)
* elevated levels of triterpenoids, which contribute sweetness

57
Q

American oak species

A

Quercus alba
* denser, less tannin, higher concentration of oak lactones, resulting in more vanilla and coconut flavors

58
Q

French Oak
- species
- forests

A

Typically a blend of 2 species: Quercus Rober / Quercus Petraea (Sessilis)

Cool climate/less fertile soil = slow growth, tighter grain
1) Troncais
2) Allier
3) Jupilles

Medium-grain
4) Nevers
5) Bertrange

Looser-grain
6) Vosges

7) Limousin (coarse-grained, preferred for spirits)

59
Q

Hungarian Oak

A

Zemplén Hills
95 - 100% Q. Petraea
*tight grained

60
Q

Preferred oak source for spirits?

A

Limousin Oak - Q. Robur, coarse grains

61
Q

Humidity’s relationship with wine maturing in barrel

A

70% humidity = water, alc evaporate at same rate

70%+ = alcohol evaporates faster, ABV decreases in time

-70% = water evaporates faster, ABV increases

62
Q

Ouillage

A

Topping up - occurs every 2 - 6 weeks during maturation
* necessary to prevent oxidation / microbial and acetic acid growth

Alternative methods:
* store barrels on side to minimize oxidation that enters through bunghole
*open barrels as little as possible

63
Q

Free SO2 vs. Bound SO2

A

Free: added SO2 that is avl to protect from oxidation and microbial spoilage. Highly reactive, binds to many components incl tannin, acid sugar
*wines with high RS/solids (like lees) need more free SO2 since higher proportion becomes bound

Bound: does not protect the wine

64
Q

Sulfur Pre-Fermentation

A
  • inhibits oxidation enzymes
  • slows yeast growth
  • inhibits bacteria
    White grapes/damaged fruit typically see more. Binds quickly, will be consumed in ferment
65
Q

Sulfur During Fermentation

A

Sulfur eats yeasts so this would only be for a specific purpose
* arrest fermentation - if RS is desired
* added immediately after primary ferment to prevent malolactic
* maintaining a certain level of SO2 is necessary for wines that are not sugar/malo dry to prevent spontaneous fermentation during aging

66
Q

Racking

A

Soutirage
Cellar operation that clarifies and aerates wine.
* wine is transferred and settled solids (lees, etc) are left in the tank
* desired clarity, lees contact, and oxidation are considerations in deciding racking frequency
* typically racked 1x - up to 6 to mature tannin/clarify further
* “reductive” methods rack minimally and protect with inert gas in process

67
Q

Scorpion

A

Standard test used in the US to detect brett/microbial spoilage

68
Q

Stardard Burgundy barrel

A

Pièce
228L

69
Q

Cognac vs Armagnac Barrels

A

Cognac Barrel = 350L
Armagnac Pièce = 400 - 420L

70
Q

Champagne barrel size

A

205L

71
Q

S. Rhone Demi-Muid size

A

600L

72
Q

Liters in a Mosel Fuder

A

1000L

73
Q

Bota Chica

A

Jerez
Shipping Butt
500L

74
Q

Liters in a Jerez Butt

A

600 - 650L
(Bota Chica = Shipping Butt = 500L)

75
Q

Liters in a Madeira Pipe

A

(shipping)
418L

[ Jerez Bota Chica = 500L; Port = 534.24; Marsala = 423L]

76
Q

Liters in a Marsala Pipe

A

423L (shipping)

77
Q

Caratelli size

A

50 - 225L
Vin Santo production

78
Q

Tokay aging barrel + size

A

Gönc
approx 136L

79
Q

Liters in standard Am. Oak Whiskey barrel

A

190L

80
Q

Liters in standard Aussie Hogshead

A

300L

81
Q

Cold stabilization

A

GOAL: reduce likelihood of crystals forming in bottle (cosmetic defect). *Standard for white wine, reds’ phenolic compounds increase solubility of tartrates so not as common
*Reduced temp = tartrates become less soluble and form crystals

METHODS:
1. refrigerate, then rack wine off tartrates
2. additives to inhibit tartrates - gum arabic, mannoproteins
3. electrodialysis

*alters acid: removal of tartrate salts decreases TA. pH 3.8 or higher increases pH. 3.8 of below decreases pH

82
Q

Methods to manage Brett

A
  1. cellar hygeine
  2. maintain a low PH
  3. low RS levels
  4. stay on top of sulfur levels
  5. minimize oxygen exposure
83
Q

Preventing re-fermentation in bottle

A

RS or incomplete malo
*sterile filtration
*SO2 addition

84
Q

Methods to remove Brett at bottling

A

The only things that can kill it…
1. pasteurization
2. the addition of Velcorin
AND
The only thing that can remove it
3. sterile filtration

85
Q

Continuous Method

A

Developed in USSR - used in Portugal and Germany for cheap fizz
* 5 tanks under pressure - base wine sugar and yeast go in one end to begin secondary - yeasts cannot grow under pressure and are added coninuously. Spent yeasts are filtered through tanks 2 and 3 - emerges clear after 4 and 5 tanks without yeasts
**3- 4 weeks total

86
Q

French term for Charmat

A

Cuvee Close (sealed tank)

87
Q

Charmat method

A

Cuvee close, granvas, autoclave
Base wines + yeast, sugar held in bulk pressure tank go under rapid ferment - ferment is then arrested by cooling wine to 23ºF when 5 atmospheres is reached

*most likely to taste like still wine with bubbles in it

88
Q

Methode Ancestral

A

Lightly sparkling with some sweetness and sediment
* young wine bottled with some RS - ferment continues in bottle and gives off CO2

89
Q

Methode Dioise Ancestrale

A

Twist on ancestral method. Used for Clairette de Die Tradition. Also used for Asti.

  • base wines ferment in stainless steel tank at low temps over several months - filtered to remove most of the yeast, bottled, and then fermentation continues to 7 - 8.5% ABV.
  • disgorged 6 - 12 months after bottlings (min. 4 months on lees) before another filtration then transferred to new bottles
    (no dosage/tirage)

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